Initially, reference is made to my prior U.S. Pat. Nos. Re. 29,494, and 3,994,415. The arrangement shown in U.S. Pat. No. 3,994,415 has proved to be particularly useful for certain applications. In the arrangement shown in this last-mentioned patent, the balanced lid is provided with rollers which ride on the upper rim of a commercial trash bin as the balanced lid is partially opened in the upright position. A pair of additional rollers extend inwardly from the rear corners of the lid and engage a curved track which is fixed to the upper rear sides of the commercial trash bin. As the lid is partially opened in the upright orientation, the rollers at the rear corners of the lid are guided downwardly in the two tracks and the supporting rollers near the center of gravity of the lid roll back along the upper surface of the trash bin until a stop is engaged. When the trash bin is inverted to empty it, the lid rotates about the pins in the upper end of the generally vertically extending track. Then, however, when the trash bin is shaken, to completely empty all waste or trash material from it, the lid is vibrated in the vertical plane in an irregular manner and occasionally one of the pins slides up the vertically extending track and jams or deforms either the lid or the track as a result of the uneven stresses which occur when one pin, but not the other, rides up in its track.
A principal object of the present invention is to avoid this damage which has occurred in balanced lid type trash bin systems utilizing roller and track guides.